1. Field of Invention
The present invention relates to a correction curve generating method, an image display method, an image display unit, and a storage medium, capable of correcting the influence of an external environment on output image.
2. Description of the Related Art
In case of using an image display unit such as a projector, it is important that an image intended by a producer be reproducible even if an external environment changes. As such a way of thinking of adjusting the visibility of image, there is known a way of thinking called color management in which input and output characteristics of a device are managed to reproduce color. But a concrete color management method taking changes of a working environment into account has not been made clear. Particularly, unless a change in brightness or color of external illumination, or color of projection plane is taken into account as a change of a working environment, it is difficult to make an appropriate reproduction of color. Generally, as the brightness of external illumination increases, the contrast of an output image in an image display unit decreases, making an appropriate color reproduction impossible. For example, even in case of displaying the same white, the displayed white may look somewhat yellowish, depending on the type of a projection plane used.
The present invention has been accomplished for solving the above-mentioned problem and it is an object of the invention to provide a correction curve generating method, an image processing method, an image display unit, and a storage medium, capable of making an appropriate color reproduction even with a change in external environment.
According to the present invention as described in claim 1, a method for generating correction curves for correcting image data inputted to an image display unit, includes: a 1st correction curve generating step of generating a 1st correction curve based on an tone reproduction characteristic in an illuminated surround of the image display unit under illumination of a predetermined luminance value, the tone reproduction characteristic in an illuminated surround having been approximated to an tone reproduction characteristic in a dark surround of the image display unit; a 2nd correction curve generating step of generating a 2nd correction curve for eliminating a difference between a reflection characteristic for each color component of an output provided from the image display unit and reflected by a predetermined projection plane and a reflection characteristic for each color component of the output provided from the image display and reflected by a reference projection plane; and a 3rd correction curve generating step of generating a 3rd correction curve which eliminates a difference in color components ratios of a predetermined external illumination.
According to the thus constructed method for generating correction curves for correcting image data inputted to an image display unit, a 1st correction curve is generated by a 1st correction curve generating step based on an tone reproduction characteristic in an illuminated surround of the image display unit under illumination of a predetermined luminance value, the tone reproduction characteristic in an illuminated surround having been approximated to an tone reproduction characteristic in a dark surround of the image display unit. By a 2nd correction curve generating step, generated is a 2nd correction curve for eliminating a difference between a reflection characteristic for each color component of an output provided from the image display unit and reflected by a predetermined projection plane and a reflection characteristic for each color component of the output provided from the image display and reflected by a reference projection plane. By a 3rd correction curve generating step, generated is a 3rd correction curve which eliminates a difference in color components ratios of a predetermined external illumination.
According to the present invention as described in claim 2, a method for performing an image processing for image data inputted to an image display unit, uses a 1st correction curve based on an tone reproduction characteristic in an illuminated surround of the image display unit under illumination of a predetermined luminance value, the tone reproduction characteristic in an illuminated surround having been approximated to an tone reproduction characteristic in a dark surround of the image display unit; a 2nd correction curve for eliminating a difference between a reflection characteristic for each color component of an output provided from the image display unit and reflected by a predetermined projection plane and a reflection characteristic for each color component of the output provided from the image display and reflected by a reference projection plane; and a 3rd correction curve which eliminates a difference in color components ratios of a predetermined external illumination.
The present invention as described in claim 3, is the method according to claim 2, wherein an image processing for image data using the 3rd correction curve is performed after an image processing for image data using the 1st correction curve and the 2nd correction curve.
The present invention as described in claim 4, is the method according to claim 2, having a plurality of 1st correction curves obtained using different the predetermined luminance values.
The present invention as described in claim 5, is the method according to claim 2, wherein the desired input tone range includes a middle tone range and the vicinity thereof.
The present invention as described in claim 6, is the method according to claim 2, wherein the tone reproduction characteristic in a dark surround and the tone reproduction characteristic in an illuminated surround are normalized to a predetermined luminance range, and in the desired input tone range of input image data the normalized tone reproduction characteristic in an illuminated surround is approximated to the normalized tone reproduction characteristic in a dark surround.
The present invention as described in claim 7, is the method according to claim 2, wherein the degree of approximation is adjustable.
The present invention as described in claim 8, is the method according to claim 4, including a 1st selection step of selecting one of plural 1st correction curves on the basis of a luminance value of external illumination, and wherein the input image data is subjected to an image processing on the basis of the selected 1st correction curve.
According to the present invention as described in claim 9, the method according to claim 8, further includes a step of inputting the luminance value of external illumination used in the 1st selection step.
According to the present invention as described in claim 10, the method according to claim 8, further includes a step of measuring the luminance value of external illumination used in the 1st selection step.
According to the present invention as described in claim 11, an image processing method according to claim 2, uses a plurality of 2nd correction curves for a plurality of projection planes.
The present invention as described in claim 12, is an image processing method according to claims 2, wherein the amount of correction of input image data corrected by the 2nd correction curve(s) is adjustable.
According to the present invention as described in claim 13, an image processing method according to claim 11, includes a 2nd selection step of selecting one 2nd correction curve from among the plural 2nd correction curves on the basis of a reflection characteristic for each color component reflected by a projection plane, and wherein an image processing is performed for input image data on the basis of the selected 2nd correction curve.
According to the present invention as described in claim 14, an image processing method according to claim 13, further includes a step of inputting the reflection characteristic for each color component reflected by the projection plane in the 2nd selection step.
According to the present invention as described in claim 15, an image processing method according to claim 13, further include a step of measuring the reflection characteristic for each color component reflected by the projection plane in the 2nd selection step.
According to the present invention as described in claim 16, the image processing method according to claim 2, uses a plurality of 3rd correction curves for each of plural external illuminations different in color components ratios.
The present invention as described in claim 17, is the image processing method according to claim 2, wherein the difference in color components ratios of the predetermined external illumination is eliminated by offsetting the difference.
The present invention as described in claim 18,, is the image processing method according to claim 17, wherein the amount of the offset is determined by subtracting each color component from an average of color components.
The present invention as described in claim 19, is the image processing method according to claim 17, wherein the amount of the offset is adjustable.
The present invention as described in claim 20, is the image processing method according to claim 16, including a 3rd selection step of selecting one 3rd correction curve from a plurality of generated 3rd correction curves on the basis of color components ratios of the predetermined external illumination, and wherein an image processing is performed for input image data on the basis of the selected 3rd correction curve.
According to the present invention as described in claim 21, the image processing method according to claim 20, further includes a step of inputting color components ratios of the external illumination in the 3rd selection step.
According to the present invention as described in claim 22, the image processing method according to claim 20, further includes a step of measuring color components ratios of the external illumination in the 3rd selection step.
The present invention as described in claim 23, is an image processing method according to claim 2, including the step of generating a final correction curve on a basis of the 1st correction curve, the 2nd correction curve and the 3rd correction curve, and wherein the final correction curve is subjected to a rounding process in a low graduation region and in a high graduation region.
The present invention as described in claim 24, is an image processing method according to claim 23, wherein the degree of the rounding process is adjustable.
The present invention as described in claim 25, is an image display unit for performing an image processing for an inputted image data, wherein the image display unit performs the image processing for the inputted data based on the 1st correction curve, the 2nd correction curve and the 3rd correction curve, which are sequentially generated by sequentially repeating the 1st correction curve generating step, the 2nd correction curve generating step and the 3rd correction curve generating step, which are described in claim 1.
According to the present invention as described in claim 26, an image display unit for performing an image processing for an inputted image data, uses: a 1st correction curve based on an tone reproduction characteristic in an illuminated surround of the image display unit under illumination of a predetermined luminance value, the tone reproduction characteristic in an illuminated surround having been approximated to an tone reproduction characteristic in a dark surround of the image display unit; a 2nd correction curve for eliminating a difference between a reflection characteristic for each color component of an output provided from the image display unit and reflected by a predetermined projection plane and a reflection characteristic for each color component of the output provided from the image display and reflected by a reference projection plane; and a 3rd correction curve which eliminates a difference in color components ratios of a predetermined external illumination.
According to the present invention as described in claim 27, the image display unit according to claim 26, has a plurality of 1st correction curves obtained using different the predetermined luminance values.
According to the present invention as described in claim 28, an image processing image display unit according to claim 26, uses a plurality of 2nd correction curves for a plurality of projection planes.
According to the present invention as described in claim 29, the image processing image display unit according to claim 26, uses a plurality of 3rd correction curves for each of plural external illuminations different in color components ratios.
The present invention as described in claim 30, is the image display unit according to claim 25, wherein an image processing for image data using the 3rd correction curve is performed after an image processing for image data using the 1st correction curve and the 2nd correction curve.
The present invention as described in claim 31, is the image display unit according to claim 25, wherein the desired input tone range includes a middle tone range and the vicinity thereof.
The present invention as described in claim 32, is the image display unit according to claim 25, wherein the tone reproduction characteristic in a dark surround and the tone reproduction characteristic in an illuminated surround are normalized to a predetermined luminance range, and in the desired input tone range of input image data the normalized tone reproduction characteristic in an illuminated surround is approximated to the normalized tone reproduction characteristic in a dark surround.
The present invention as described in claim 33, is the image display unit according to claim 25, wherein the degree of approximation is adjustable.
The present invention as described in claim 34, is an image processing image display unit according to claim 25, wherein the amount of correction of input image data corrected by the 2nd correction curve(s) is adjustable.
The present invention as described in claim 35, is the image processing image display unit according to claim 25, wherein the difference in color components ratios of the predetermined external illumination is eliminated by offsetting the difference.
The present invention as described in claim 36, is the image processing image display unit according to claim 35, wherein the amount of the offset is determined by subtracting each color component from an average of color components.
The present invention as described in claim 37, is the image processing image display unit according to claim 35, wherein the amount of the offset is adjustable.
According to the present invention as described in claim 38, the image display unit according to claim 27, includes a 1st selection unit for selecting one of plural 1st correction curves on the basis of a luminance value of external illumination, and wherein the input image data is subjected to an image processing on the basis of the selected 1st correction curve.
According to the present invention as described in claim 39, the image display unit according to claim 38, further includes a unit for inputting the luminance value of external illumination used in the 1st selection unit.
According to the present invention as described in claim 40, the image display unit according to claim 38, further includes a unit for measuring the luminance value of external illumination used in the 1st selection unit.
The present invention as described in claim 41, is an image processing image display unit according to claim 28, including a 2nd selection unit for selecting one 2nd correction curve from among the plural 2nd correction curves on the basis of a reflection characteristic for each color component reflected by a projection plane, and wherein an image processing is performed for input image data on the basis of the selected 2nd correction curve.
According to the present invention as described in claim 42, an image processing image display unit according to claim 41, further includes a unit for inputting the reflection characteristic for each color component reflected by the projection plane in the 2nd selection unit.
According to the present invention as described in claim 43, an image processing image display unit according to claim 41, further includes a unit for measuring the reflection characteristic for each color component reflected by the projection plane in the 2nd selection unit.
The present invention as described in claim 44, is the image processing image display unit according to claim 29, including a 3rd selection unit for selecting one 3rd correction curve from a plurality of generated 3rd correction curves on the basis of color components ratios of the predetermined external illumination, and wherein an image processing is performed for input image data on the basis of the selected 3rd correction curve.
According to the present invention as described in claim 45, the image processing image display unit according to claim 44, further includes a unit for inputting color components ratios of the external illumination in the 3rd selection unit.
According to the present invention as described in claim 46, the image processing image display unit according to claim 44, further includes a unit for measuring color components ratios of the external illumination in the 3rd selection unit.
The present invention as described in claim 47, is an image processing image display unit according to claim 25, including the unit for generating a final correction curve on a basis of the 1st correction curve, the 2nd correction curve and the 3rd correction curve, and wherein the final correction curve is subjected to a rounding process in a low graduation region and in a high graduation region.
The present invention as described in claim 48, is an image processing image display unit according to claim 47, wherein the degree of the rounding process is adjustable.
According to the present invention as described in claim 49, a computer-readable medium storing correction curves to perform an image processing for image data inputted to an image display unit, includes: a 1st correction curve based on an tone reproduction characteristic in an illuminated surround of the image display unit under illumination of a predetermined luminance value, the tone reproduction characteristic in an illuminated surround having been approximated to an tone reproduction characteristic in a dark surround of the image display unit; a 2nd correction curve for eliminating a difference between a reflection characteristic for each color component of an output provided from the image display unit and reflected by a predetermined projection plane and a reflection characteristic for each color component of the output provided from the image display and reflected by a reference projection plane; and a 3rd correction curve which eliminates a difference in color components ratios of a predetermined external illumination.
The present invention as described in claim 50, is a computer-readable medium having a program of instructions for execution by the computer to perform an image processing for image data inputted to an image display unit, wherein the image processing corrects input image data by using: a 1st correction curve based on an tone reproduction characteristic in an illuminated surround of the image display unit under illumination of a predetermined luminance value, the tone reproduction characteristic in an illuminated surround having been approximated to an tone reproduction characteristic in a dark surround of the image display unit; a 2nd correction curve for eliminating a difference between a reflection characteristic for each color component of an output provided from the image display unit and reflected by a predetermined projection plane and a reflection characteristic for each color component of the output provided from the image display and reflected by a reference projection plane; and a 3rd correction curve which eliminates a difference in color components ratios of a predetermined external illumination.
The present invention as described in claim 51, is the computer-readable medium according to claim 50, wherein an image processing for image data using the 3rd correction curve is performed after an image processing for image data using the 1st correction curve and the 2nd correction curve.
According to the present invention as described in claim 52, the computer-readable medium according to claim 50, has a plurality of 1st correction curves obtained using different the predetermined luminance values.
The present invention as described in claim 53, is the computer-readable medium according to claim 50, wherein the desired input tone range includes a middle tone range and the vicinity thereof.
The present invention as described in claim 54, is the computer-readable medium according to claim 50, wherein the tone reproduction characteristic in a dark surround and the tone reproduction characteristic in an illuminated surround are normalized to a predetermined luminance range, and in the desired input tone range of input image data the normalized tone reproduction characteristic in an illuminated surround is approximated to the normalized tone reproduction characteristic in a dark surround.
According to the present invention as described in claim 55, is the computer-readable medium according to claim 51, wherein the degree of approximation is adjustable.
The present invention as described in claim 56, is the computer-readable medium according to claim 52, including a 1st selection step of selecting one of plural 1st correction curves on the basis of a luminance value of external illumination, and wherein the input image data is subjected to an image processing on the basis of the selected 1st correction curve.
According to the present invention as described in claim 57, the computer-readable medium according to claim 56, further includes a step of inputting the luminance value of external illumination used in the 1st selection step.
According to the present invention as described in claim 58, the computer-readable medium according to claim 56, further includes a step of measuring the luminance value of external illumination used in the 1st selection step.
The present invention as described in claim 59, is an image processing computer-readable medium according to claim 50, which uses a plurality of 2nd correction curves for a plurality of projection planes.
The present invention as described in claim 60, is an image processing computer-readable medium according to claim 50, wherein the amount of correction of input image data corrected by the 2nd correction curve(s) is adjustable.
The present invention as described in claim 61, is an image processing computer-readable medium according to claim 59, including a 2nd selection step of selecting one 2nd correction curve from among the plural 2nd correction curves on the basis of a reflection characteristic for each color component reflected by a projection plane, and wherein an image processing is performed for input image data on the basis of the selected 2nd correction curve.
According to the present invention as described in claim 62, an image processing computer-readable medium according to claim 61, further includes a step of inputting the reflection characteristic for each color component reflected by the projection plane in the 2nd selection step.
According to the present invention as described in claim 63, an image processing computer-readable medium according to claim 61, further includes a step of measuring the reflection characteristic for each color component reflected by the projection plane in the 2nd selection step.
According to the present invention as described in claim 64, the image processing computer-readable medium according to claim 50, uses a plurality of 3rd correction curves for each of plural external illuminations different in color components ratios.
The present invention as described in claim 65, is the image processing computer-readable medium according to claim 50, wherein the difference in color components ratios of the predetermined external illumination is eliminated by offsetting the difference.
The present invention as described in claim 66, is the image processing computer-readable medium according to claim 65, wherein the amount of the offset is determined by subtracting each color component from an average of color components.
The present invention as described in claim 67, is the image processing computer-readable medium according to claim 65, wherein the amount of the offset is adjustable.
The present invention as described in claim 68, is the image processing computer-readable medium according to claim 64, including a 3rd selection step of selecting one 3rd correction curve from a plurality of generated 3rd correction curves on the basis of color components ratios of the predetermined external illumination, and wherein an image processing is performed for input image data on the basis of the selected 3rd correction curve.
According to the present invention as described in claim 69, the image processing computer-readable medium according to claim 68, further includes a step of inputting color components ratios of the external illumination in the 3rd selection step.
According to the present invention as described in claim 70, the image processing computer-readable medium according to claim 68, further includes a step of measuring color components ratios of the external illumination in the 3rd selection step.
The present invention as described in claim 71, is an image processing computer-readable medium according to claim 50, including the step of generating a final correction curve on a basis of the 1st correction curve, the 2nd correction curve and the 3rd correction curve, and wherein the final correction curve is subjected to a rounding process in a low graduation region and in a high graduation region.
The present invention as described in claim 72, is an image processing computer-readable medium according to claim 71, wherein the degree of the rounding process is adjustable.